JPH0912116A - Method for planning change of container arrangement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an optimal carrying plan by deciding the grouping of all the material to be carried into plural sets so that the total of the loading time over the full sets becomes the minimum, and deciding the carrying order of the plural sets so that the total of the vacant time over the full sets becomes the minimum. SOLUTION: Containers are piled at multiple stages in a container yard. Working time per each pair of the containers of the top stage at that time is computed. Next, the maximum matching subject is solved so as to obtain the optimal grouping of all the pairs. In the case where a software for the minimum subject is used, it is necessary to be converted for the maximum matching subject, and the maximum matching subject is solved. Moving time between each pair is computed over all the pairs. At this stage, carrying order of each pair is decided over all or a part of the pairs. Since two-stage piling and one-stage piling exist in each block, all or a part of the pairs are handled over all the blocks. When a residual container is not detected, the operation is concluded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a container relocation plan for a container yard or the like, and more particularly to an optimizing planning method for minimizing the time required for relocating a transfer item in a storage space.

[0002]

2. Description of the Related Art Conventionally, the following method has been adopted when preparing a rearrangement plan for containers such as a container yard. 1) Method of searching all transfer plans All the transfer plans that can be executed are enumerated, and the transfer time for each of them is calculated and compared to find the transfer plan with the minimum transfer time. 2) Method of determining transport order without anticipating mutual interference First, calculation is performed only from the moving distance determined by the starting position and the arriving position of each conveyed object without anticipating the operation due to mutual interference of a plurality of conveying means. The transportation plan is completed by determining the transportation order based on the required time and then adding the operation due to the mutual interference that occurs when the transportation means performs the work according to the transportation order.

[0003]

However, the above-mentioned method for searching all the transportation plans has a problem that the calculation time becomes huge. Further, in the method of determining the transport order first without anticipating the mutual interference, there is a problem that the optimality of the transportation plan is impaired by the addition of the operation due to the mutual interference later. By the way, in the case where each position in the yard is a first-in, first-out arrangement in which a plurality of conveyed items can be placed: -The order of first-in, first-out is maintained- It is necessary to create the optimal transport plan after satisfying the condition of being equalized, but the optimal transport plan of the transport products of all ranks at all positions should be prepared by a unified means that can satisfy all of these conditions. It was difficult to make by the conventional technology. That is, in the conventional technology, since the means for satisfying the above conditions and the means for optimizing the transportation plan lack uniformity, there is a problem that the optimality of the transportation plan is impaired. is there.

The present invention has been made to solve the above-mentioned problems, and an optimum transportation plan for rearranging a large number of transported objects in a short time is determined by the start position and the arrival position of the transported objects. It is created based on the required time calculated in consideration of the movement due to mutual interference as well as the defined movement distance. Also, it is a first-in, first-out method in which each position in the yard can hold multiple objects. Even if it is an array, all the rankings of all positions are unified by a unified means that can satisfy all the conditions that the constraint by the order of last-in, first-out is kept and the length reduction of each array is equalized. It is an object of the present invention to provide a container rearrangement creation planning method that makes it possible to create an optimal transfer plan for the above-mentioned transported objects.

[0005]

According to one embodiment of the present invention, there is provided a container rearrangement plan creating method in which a large number of articles are distributed and arranged at a plurality of positions in a storage area whose whole area is divided by coordinates. In the container rearrangement plan preparation method for rearranging a container from a current storage location to a prespecified destination location by using a plurality of (N) transfer means operating on the same orbit, the following processing steps are included. . (A) A load time required from the start to the end of the transfer of one set, where N sets are a combination of N or less objects that can be carried at a time by the N transfer means in synchronization. And a step of calculating an empty time required for movement between sets from the end of the conveyance of the previous set to the start of the conveyance of the next set, in consideration of the time required for the retracting operation and the waiting operation due to the mutual interference of the conveying means. (B) A step of determining the grouping of all the conveyed articles into a plurality of sets so that the total sum of the load times obtained in the step (a) over all the sets is minimized. (C) A step of determining the transport order of the plurality of sets such that the total sum of the empty time obtained in the step (a) over all the sets is minimized. Therefore, in one aspect of the present invention, it is possible to calculate all of the load times and the vacant times of the N transfer means in consideration of the operation due to mutual interference of the transfer means. Then, by determining the grouping of the conveyed items into sets by using, for example, a solution method of the weighted maximum matching problem, it is possible to obtain an optimum combination over all the sets. In addition, the transport order of a plurality of sets can be set to an optimum order over all the sets by, for example, determining using a solution method for the traveling salesman problem.

A container rearrangement plan creating method according to another aspect of the present invention uses block numbers as the storage location and the destination location in the above method. By using the block number as the storage location and the destination location in this way, the constraint condition that the containers must be processed in order from the upper stack is automatically satisfied, and the algorithm becomes complicated. It can be avoided and the calculation time can be shortened.

A container rearrangement plan creating method according to another aspect of the present invention is a first-in, first-out arrangement in which a plurality of articles can be placed at individual positions in the storage area. In some cases, in the step (b), all the conveyed items in each array that are in the retrievable order are grouped into a set, and in the step (c), the step (b) is performed. The transfer order is determined for all or some of the sets generated in the process (4), and these processes (b) and (c) are combined to form a single transfer plan. Then, by carrying out the repeat of the transport plan, which is the new target of the next plan, the transportable items in each array remaining after the previous creation are repeated until there are no remaining plan targets, To complete the optimum transportation plan for the transported materials in the order. Therefore,
In another aspect of the present invention, even if each position in the storage area is a first-in, first-out arrangement in which a plurality of articles can be placed, the restriction by the order of last-in first-out is maintained, and It is possible to create an optimal transport plan for the transport products of all ranks by a unified means that can satisfy all the conditions of equalizing the reduction of the length (: number of stages) of each array.

Further, in the container rearrangement plan creating method according to another aspect of the present invention, the lengths of the remaining arrays are all 1 in the step (c) at each time of repeating the transfer plan. In the case (: When the number of stages is all 1 stage), the transport order is determined for all the sets, and when the array length is 2 or more (: When there are 2 or more stages) Determines the transfer order for only some sets. Then, when the transport order is determined for only some of the sets, the set including the transported material at the position where the remaining array length is long is preferentially taken into the planning target. For example, as shown in FIG. 11A, when there are two stacked containers remaining, it is assumed that the uppermost container at this point is processed by the process of (b) above (7, 6) Once (7, 6) rather than treating all 3 pairs of (2, 4) (9, 5) in the step (c) above
If the processing of the step (c) is performed on only two pairs of (2, 4), then the processing of the step (b) is performed on the newly appearing uppermost container, The cotainer 9 is paired with the container 12 below the container 6, that is, (9,12) may be processed in the step (c), and processed as a pair (9,5). The result may be better than
For this reason, when the multi-tiered stack remains, the set of conveyed products processed in the step (c) is not all the sets generated in the step (b), but a part of the set. (:
In the above example, only 2 pairs of (2, 4) and (7, 6) are used. Furthermore, as shown in FIG. 11 (b), when a mountain with a high step number and a mountain with a low step number coexist, the mountain with a high step number is preferentially processed to prevent the remaining mountain number from decreasing. I'm out. In FIG. 11B, (1, 3) (2, 5)
Of the 3 pairs of (4, 6), if the pair of (1, 3) is processed at this point, the number of remaining mountains becomes 4, but (2
5) The two pairs of (4, 6) are processed preferentially (1, 3)
If you leave the pair, you will have 6 remaining mountains. If the number of remaining mountains is small and there is only one, for example, two cranes will interfere. In other words, the greater the number of remaining mountains, the more efficient the transportation plan can be created. Therefore, in another aspect of the present invention, even if each position in the storage space is a first-in, first-out arrangement in which a plurality of articles can be placed, the restriction by the order of last-in, first-in is maintained. It is possible to create an optimal transportation plan for the transported materials of all ranks by a unified means that can satisfy all the conditions that the length of each array is reduced and the reduction of the length of each array are equalized. Further, in the plan repetition applied in the case of the array of the first-in first-out method, by equalizing the reduction of the length of each array, one transporting means transports from the array position left alone in isolation. It is possible to prevent the occurrence of an inefficient situation in which the other transport means is kept waiting while the article is being taken out.

[0009]

FIG. 2 is a diagram showing a container yard to which a container rearrangement creating method according to an embodiment of the present invention is applied, and FIG. 3 shows a system configuration to which the above embodiment is applied. It is a figure. In the present embodiment,
A case where there are two transport means will be described. That is, in this embodiment, the buffer area 21 as shown in FIG.
In the container yard divided into two areas, the stack area 22 and the stack area 22, the container replacement work between the two areas is performed by two RMGs (Rail Mounted Gant).
An example of a system for creating a transportation plan to be carried out in the shortest time using the ry cranes 31 and 32 will be described.

As shown in FIG. 3, the system according to the present embodiment is constructed by connecting a computer 1 for creating an optimum transportation plan and a computer 2 for managing the operation of the entire container terminal by a network 10. Further, the computer 2 stores a database 3 in which information such as the size and weight of each container and information such as the location in the yard, and the setting input of conditions necessary for planning and the result of planning are stored. An input / output device 4 for displaying is connected. If the production method according to the present embodiment is applied to this container yard, the optimization of the transportation plan in this case can be reduced to the following two-stage optimization problem.

First stage: Pairing
Problem Pair all the containers to be shifted into two pairs of containers that the two RMGs 31 and 32 carry in synchronization.
It should be noted that it is acceptable as a dummy pair that one unit can carry one unit and the other one can operate synchronously with an empty load. Second stage: Sequencing problem The processing order of all paired container pairs is determined.

FIG. 4 is a diagram showing the overall concept of the optimization problem divided into the above two stages. Here, in the generation of the pair of containers in the first stage, A (1,3), B
(2,6), C (4,5), D (7,8), E (9,1)
1), a pair F (10,12) is generated. In the processing order of the second stage container, D
(7,8) → B (2,6) → F (10,12) → A
The processing order of (1,3) → E (9,11) → C (4,5) is determined.

FIG. 5 is a diagram showing a state in which the transfer plan of FIG. 4 is executed, and the above-described processing is performed by reciprocating the RMGs 31 and 32 of FIG. 2 between the buffer area 21 and the stack area 22. Follow the order for lifting / lowering the Konathena.

(First-stage optimization): For the first-stage optimization, the sum of "working time in units of one pair" over all pairs should be minimized. Here, the working time of one pair unit is a load time required for the two RMGs 31 and 32 to synchronously carry one pair of container pairs from the departure position to the arrival position. To calculate the working time in units of 1 pair, the departure position and the arrival position of each container, the minimum accessible distance of two RMGs, the right end limit position and the left end limit position of the RMG travel span, the RMG travel speed, and the RMG Using the hoisting time and hoisting time of the container hoisting and unwinding as a specification data, calculate the required operation time according to the presence or absence of mutual interference between the two RMGs 31 and 32.

FIG. 6 is a diagram showing an example of the above calculation. The calculation method of FIG. 6 is similarly applied to the case of a dummy pair (one is empty). In FIG. 6, RMG3
The assumption is that 2 moves first and RMG 31 moves thereafter. The conditions of calculation, the calculation of working time, the standard initial position and the standard end position are respectively expressed by the following equations. 1) Calculation conditions a) Xj ≤ Xi: Since j is located to the left of i, R
MG31 carries j and RMG32 carries i. b) Xi −Δ <Xj <Xi + Δ: the starting positions of i and j are Δ
Due to the closer proximity, mutual interference occurs on departure. c) Yj≤Yi-Δ: Since the arrival positions of i and j are farther than Δ, mutual interference does not occur when they arrive. 2) Working time Tij = {2 * W + | Yj-Xj | / V} + {W + | Xj
-Xi + Δ | / V} In the above equation, {2 * W + | Yj-Xj | / V}
Is the working time of the RMG31 to be subsequently generated, "2 * W" is the sum of the suspending operation time and the descending operation time of the RMG31, and "| Yj-Xj | / V" means that the RMG31 is the container j.
It is the time from the departure position Xj to the arrival position Yj. {W + | Xj-Xi + Δ | / V} is a time difference generated between the starting RMG 32 and the starting RMG 31 in the mutual interference occurring at the time of departure, and “W” indicates that the starting RMG 32 suspends the starting RMG 32. Waiting time, "| Xj-Xi + △ | / V" is the starting RMG
This is the time from when the subsequent RMG 31 reaches the starting position Xj of the container j from the standard initial position Xi-Δ after the suspension operation of 32 is completed.

3) Standard initial position RMG31: Xi-Δ RMG32: Xi 4) Standard end position RMG31: Yi RMG32: Section [max {Yj + Δ, Yi- (Tij-T
j) * V}, min {Yj + (Tij-Tj) * V, Lmax
}] Where Tj = 2 * W + | Yj-Xj | / V In the above equation, {Yj + [Delta], Yi- (Tij-Tj
) * V}, when the next winding position is on the left side of Yi,
It indicates that the vehicle moves to the left as long as the time to the interference limit position allows. {Yj + (Tij-Tj) * V, Lmax}
Indicates the maximum movement length within the yard, and the next winding position is Y
In the case of the right side of i, it indicates that the movement is limited to the physical rail length.

In the present embodiment, as described above,
In the process of calculating the working time for each pair, the “standard initial position” and the “standard end position” are obtained as the location positions of the two RMGs 31, 32 at the work start time and the work end time. The standard initial position and standard end position are the values used to calculate the “movement time between pairs” in the second stage optimization. The minimization of the total sum of the working time of one pair unit means that the working time of one pair unit is calculated for all the pairs that can be combined, and the total sum of the working time of all pairs is minimized. It is to ask. This problem can be solved as a weighted maximum matching problem in graph theory if attention is paid to the following two points. -If each container is a node on the graph, the working time of each pair can be regarded as the weight of the branch between two nodes.・ The minimum value can be replaced with the maximum value by replacing the value of each branch length with the difference from a sufficiently large constant.

FIG. 7 is a diagram showing an example of the weighted maximum matching problem in the above processing. The same figure (a) is applied by applying the weighted maximum matching.
It becomes as shown in.

(Second-stage optimization): For the second-stage optimization, the total sum of the "movement time between pairs" over all pairs is to be minimized. Here, the moving time between pairs is an empty time required to move from the standard end position of the previously processed pair to the standard initial position of the pair to be processed next time. Minimizing the sum of the travel time between pairs over all pairs means calculating the travel time between pairs for every two pairs,
This is to find the shortest path that minimizes the total travel time when going through all pairs. This problem can be solved as a traveling salesman problem in graph theory.

FIG. 8 is a diagram showing an example of the traveling salesman problem. When the traveling salesman problem is applied to the route shown in FIG. 11A to find the shortest route, the route shown in FIG.

(Repeating procedure in case of multi-stage stacking): FIG.
3 is a flowchart showing a procedure of a method of creating a transportation plan. Since the containers are stacked in multiple layers in the container yard of the present embodiment, a transportation plan is created by repeating the following procedure. Step 1: Calculate the working time in units of one pair for all the containers at the top at that time. Step 2: Solve the weighted maximum matching problem and find the optimum combination of all pairs. Here, for example, when software for the minimum problem is used, it is necessary to divert it to the maximum matching, and thus such a weighted maximum matching problem is solved. Specifically, the minimum value is converted to the maximum value by subtracting the value obtained from a very large number. Step 3: Calculate the migration time between pairs for all the obtained pairs. Step 4: Decide the transfer order of each pair for all or some of the pairs. Each block also has a 2-tier stack
Since some of them are stacked, all blocks are targeted regardless of the number of stacked (block numbers are used), and all or some pairs are targeted from the viewpoint of targeting a part of two stacking. Step 5: If there are remaining containers, return to step 1. If not, end.

FIG. 9 is a flowchart in which one mode of procedure 4 is added. Procedure 4 is processed as follows.・ It is judged whether all the remaining container piles are stacked in one stack. ・ If all stacks are stacked in one stack, the transfer order is determined for all (N pairs) pairs.・ If there are multiple stacks left, some (M groups, but 0 <M <
The transfer order is determined for the pair N). It should be noted that M is obtained by M = kN using an appropriate constant k (coefficient when a part of the pair is used) in which 0 <k <1.

FIG. 10 is a flowchart in which another mode of the procedure 4 (correction of movement time between pairs for equalizing the number of stages) is added. When the multi-tiered stack remains in the procedure 4, it is processed as follows. -For the pair to which the mountain with the highest remaining number of all container mountains belongs- "Move time between pairs" from all other pairs to the corresponding pair- "Move between pairs" from the corresponding pair to all pairs Forcibly cut "time".・ By this correction, the pair to which the highest-level container mountain belongs is preferentially incorporated into the partial shortest path that passes through M (0 <M <N) nodes, and therefore the whole mountain It is possible to obtain an effect that the reduction of the number of steps of is equalized.

[0024]

As described above, according to one aspect of the present invention, one set is a combination of N or less conveyed objects that can be simultaneously conveyed by N conveying means, and the number of N conveyed objects is set. The evacuation operation by the mutual interference of the transport means is performed by the load time required for the transport means from the start of transport of one set to the end of transport and the empty time required for the movement between the sets from the transport end of the previous set to the transport start of the next set. And calculate the time required for the waiting operation, and divide all the conveyed items into multiple sets,
The total sum of the above load times over all the sets is determined to be the minimum, and the transport order of the plurality of sets is determined such that the total sum over the entire set of the above-mentioned load times is minimized. Therefore, the load time and empty time of a plurality of transport means are calculated in consideration of the operation due to the mutual interference of the transport means, and it is not necessary to add the operation due to the mutual interference later,
Therefore, the optimality is not impaired. In addition, a means that can make an optimal combination of all the sets into a set of conveyed articles and a means that can make the conveying order of a plurality of sets the optimal order of all the sets are combined. When the present invention is applied by the above method, it is possible to create a transportation plan having a short time required for relocation. In addition, since the optimization method by mathematical programming can be applied to the optimization of the grouping of the conveyed items into the set and the optimization of the conveying order of the set, in such a case, the calculation time is shortened and even a small computer can be used. A transportation plan can be created in a short time. Further, according to another aspect of the present invention, the block number is used as the storage location and the destination location, so that the constraint condition that the containers must be processed in order from the upper stack is automatically added. Is satisfied, complexity of the algorithm is avoided,
The time for calculation can be shortened.

Further, according to another aspect of the present invention, even if the arrangement of the conveyed articles is a first-in first-out arrangement in which a plurality of conveyed articles can be placed at individual positions in the storage space, Create a transport plan for transport products of all ranks at all positions by a unified means that can satisfy all the conditions that the restrictions by the order of input are kept and the length of each array is equalized. Therefore, the optimality is not impaired. In addition, in the plan iteration applied when each position in the storage area is a first-in first-out array in which a plurality of conveyed items can be placed, by equalizing the length reduction of each array. It is possible to prevent the occurrence of inefficient work in which one transfer means waits for an empty load while another transfer means waits while taking out a transfer object from an array position where it remains isolated. Therefore, it is possible to create a transportation plan that requires a short time for rearrangement.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a procedure of a method of creating a transportation plan in the above embodiment.

FIG. 2 is a diagram showing a container yard to which the production method according to the embodiment of the present invention is applied.

FIG. 3 is a diagram showing a system configuration to which the above embodiment is applied.

FIG. 4 is a diagram showing an overall concept of an optimization problem divided into two stages in the above embodiment.

FIG. 5 is a diagram showing a state when the transportation plan creation of FIG. 4 is executed.

FIG. 6 is a diagram exemplifying a method of calculating a load time and an empty time in the above embodiment.

FIG. 7 is a diagram showing a concept of a weighted maximum matching problem applied in the above embodiment.

FIG. 8 is a diagram showing a concept of a traveling salesman problem applied in the above embodiment.

FIG. 9 is a flowchart in which one mode of procedure 4 is added to FIG.

10 is a flowchart in which another aspect of procedure 4 is added to FIG.

FIG. 11 is an explanatory diagram of a creating method according to the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hajime Ase Inventor Marunouchi 1-2-2, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Inventor Tatsuya Nakajima 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date Inside the Steel Pipe Corporation (72) Inventor Shigekazu Takahashi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Inside the Nippon Steel Pipe Corporation

Claims (5)

[Claims] 1. A plurality of (N) conveying means operating on the same orbit are used to disperse a plurality of conveyed objects distributed in a plurality of positions in a storage area whose whole area is divided by coordinates. , A container rearrangement plan creation method for rearranging a current storage location to a predesignated destination position, (a) N or less transported articles that can be simultaneously transported by N transportation means 1 set, the load time required from the start of transport of one set of transport means to the end of transport, and the empty time required to move between sets from the end of transport of the previous set to the start of transport of the next set. Is calculated by taking into account the time required for the retracting operation and the waiting operation due to the mutual interference of the conveying means, and (b) grouping all the conveyed objects into a plurality of sets, the load obtained in the step (a) above. Over the entire set of time And (c) determining the order of conveyance of the plurality of sets so that the total sum over all sets of the empty time obtained in the step (a) is minimum. A method for creating a container relocation plan, comprising: 2. The container relocation plan creation method according to claim 1, wherein block numbers are used as the storage location and the destination location. 3. When the arrangement of the conveyed items is a first-in, first-out arrangement in which a plurality of conveyed objects can be placed at respective positions in the storage area, in each of the arrangements in the step (b), All the conveyed items in the order that can be taken out are grouped into sets, and in the step (c), the steps (b)
The transfer order is determined for all or some of the sets generated in the process of (1), and the processes of (b) and (c) are combined to make one transfer plan, and Optimum transportation of transportation products of all ranks at all positions by repeating the transportation plan that sets the transportable products in the order that can be taken out as a new target of the next plan until there are no remaining planning targets The method for creating a container relocation plan according to claim 1, wherein the plan is completed. 4. The step (c) of each time of repeating the transportation plan.
In the step of (1), if the lengths of the remaining sequences are all 1, the transport order is determined for all the sets, and if there are 2 or more sequences, 4. The container rearrangement plan creation method according to claim 3, wherein the transfer order is determined only for the set of. 5. When the transfer order is determined for only some of the sets, the set including the transferred products having the long remaining array length is preferentially taken into the planning target. Item 4. Container relocation plan creation method described in item 4.